Though terrestrial communication networks now reach much of the earth, there are still many regions in which an individual is not able to exchange communication information with another individual. This communication information could include voice, text or video data that the individual (“user”) desires to exchange with the other individual using a device such as a cell phone (“user device”). The user could be prevented from exchanging communication information because the user is in an environment where there are no terrestrial communication networks to provide cell service or internet access, or perhaps is in a region that does not have a terrestrial communication network that the user is authorized to use.
To receive convenient and predictable communication connectivity, the user may use a communication device that is capable of exchanging communication signals between the communication device and satellites of a satellite constellation. Examples of satellite constellations include the Global Positioning System (GPS), Galileo and GLONASS constellations for navigation and geodesy, the Iridium and Globalstar satellites for telephony services, the Disaster Monitoring Constellation and RapidEye for remote sensing, the Orbcomm satellites for messaging service, the Russian elliptic orbit Molniya and Tundra constellations and the Cospas-Sarsat search and rescue satellites.
Such satellites include Low Earth Orbiting satellites (LEOs), Geostationary Satellites (GEOs), or other satellites. LEO satellites travel at high angular velocity to maintain orbit. As a result, the coverage area provided by a LEO satellite moves as the LEO satellite travels. Thus, many LEO satellites are often needed to maintain continuous coverage over an area.
Because the coverage area provided by a LEO satellite moves, when a user wishes to initiate communications, it may be minutes or hours before a LEO satellite is above the horizon and can begin the exchange of communication signals. GEO satellites, by contrast, move at the same angular velocity as the rotation of the earth's surface and can provide permanent coverage over a large area. Thus, to maintain constant and predictable communication, GEO satellites are sometimes preferred over LEO satellites for communication.
To communicate with GEO satellites with acceptable signal strength, and to avoid interfering with other satellites or terrestrial transceivers that operate in the same frequency band as the communication device, the communication device may be designed to have a narrow antenna lobe and must point precisely towards its intended satellite before transmitting and/or receiving a communication signal. However, because such communication devices may be optimized for size, weight and portability, traditional antenna pointing systems for high accuracy antenna pointing may be undesirable or impractical.